William w



(No Model.)

W. W. GRISOOM.

ELECTED MAGNETIC SWITCH.

No. 394,485. Patented Dec. 11, 1888.

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UNITED STATES PATENT ()EEIcE.

IVILLIAM GRISGOM, OF HAVERFORD COLLEGE, PENNSYLVANIA.

ELECTRO-MAGNETIC SWITCH.

SPECIFICATION forming part of Letters Patent No. 394,485, dlted December 11, 1888.

Application filed August 10, 1888. Serial No. 282,395. (No model.)

To all whom it may concern.-

Be it known that I, IVILLIAM GRISCOM, a citizen of the United States, and a resident of Haverford College, in the county of Montgomery and State of Pennsylvania, have invented certain new and useful Improvements in Electro-Magnetic Switches, of which the following is a specification.

My invention is an improvement in electro-magnetic switches.

The object is to provide a durable and efficient automatic circuit-breaker for use in charging secondary batteries.

I provide an electro-magnetic coil of coarse wire, an armature fixed to a suitable pivoted lever, one end of which bears a counter-weight, and at the other end there is a detachable pair of contact-points in position to dip into In the free end of the armature -bar there is a slot and setscrew. The slot has its opening upon the upper side of the bar. A U-shaped copper rod is dropped into this slot from the top and the set-screw holds it in position. The improved construction described renders it possible to replace the U -shaped copper rod, should it become burned or injured, without interrupting the circuit. The change can readily be made by placing the opposite ends of a new U-shaped copper rod in the mercury-cups, and then unscrewing and withdrawing the old rod. The circuit being complete through the new rod will not be interrupted, and upon removal of the old rod the new one may be placed in the slot and screwed fast, the circuit remaining uninterrupted during the entire operation of change. The two mercurycups and the magnet are designed to be placed in series in the main charging-circuit. The mercury-cups are provided with large flaring openings to prevent dispersion of globules of mercury during the operation of the apparatus, and there is a shoulder to indicate the proper height for filling with mercury, for in instruments of this kind as at present arranged the mercury may get too low to make satisfactory contact before the defect is noticeable, and an arc is formed at the instant of'closing circuit if this is allowed to occur.

The accompanying drawings illustrate my invention.

Figure 1 is a side view, Fig. 2 a plan view, and Fig. 3 a cross section showing the improved arrangement of mercury-cups.

m is a coarse-wire electro-magnet. Armature 7" is fixed to an armature-bar, a, pivoted at p.

C is a counter-weight. At the opposite end of bar a there is a double contact-point re movably fixed to bar a by a slot and setscrew, 0. This removable double contact, when thus arranged, may easily be removed and replaced whenever burned, corroded, or injured. It is preferably formed of a copper rod or wire of large gage.

. c c are cups of brass having wide mouths or openings, and a shoulder, .5, turned on the interior surface, indicating the height to which the mercury should be supplied or introduced.

5 and 6 are screw-cups for the main conductors.

The device is a specific construction of apparatus, shown by experience and experiment to be useful in charging secondary batteries. It is connected into a circuit, the mercury-cups and magnet being in series. Normally the armature is attracted by the existing electrical current. When this current weakens to a predetermined point, the retractor C tilts the opposite end of armature-bar a upward, and the double connection n is lifted out of the mercury, opening the circuit. If a succession of sparks burns, corrodes, or destroys the double connector )2, it may be replaced by loosening the screw. The new or substitute U-shaped rod is inserted in the mercury-cups before removing the injured rod, after which the injured rod is removed and the new rod placed in position in the slot without interrupting the operation of the apparatus. The flaring mouth of the mercurycups affords space for this operation, while the amount of mercury used is limited to the size of the cups below the shoulder.

hat- I claim, and desire to secure by Letters Patent, is

In an electro-magnetic switch, the combination of an electron1agnet, an armature therefor, a bar or lever attached to the armature, U-shaped rod, whereby the said rod may be a slot at the free end of the armature-bar removed and replaced without interrupting opening upon the upper, side of said bar, a the circuit, substantially as described.

U-shaped rod removably located in said slot, WILLIAM W. GRISCOM. 5 and a pair of mercury-cups having flaring \Vituesses:

openings located upon opposite sides of the DANIEL E. DELAVAN,

armature-bar to receive opposite ends of the 'WM. 13. VANSIZE. 

